Field of the Invention
The present invention relates to a transport system and a control method thereof using a movable magnet-type linear motor (a moving magnet-type linear motor, a movable magnetic field-type linear motor) and to a processing system having the transport system.
Description of the Related Art
In general, transport systems are used in production lines for assembling industrial products. A transport system in a production line transports a work such as a component among a plurality of stations within or between factory-automated production lines. As a transport system, a transport system with a movable magnet-type linear motor has already been proposed.
In a production line, a clamp/unclamp state of a work may be changed or a processing face of a work may be changed during each working process or between the previous working process and the next working process. In such a case, the state of a work on a mover in a transport system is changed to enter the next transport or working process. Thus, there is a problem that a wide installation space is required in the production line to arrange both a transport system and an apparatus used for changing the state of a work. Further, the time for converting the state of a work is required during transport or immediately before processing of a work, and this results in a problem of an increase in the entire time required to process the work. Thus, Japanese Patent Application Laid-Open No. 2001-179568 discloses a work transport apparatus that is provided with an attitude change mechanism that moves a work stage supporting a work along a guide member to change the attitude of the work. Japanese Patent Publication No. H7-86772 discloses a transport apparatus that moves a plurality of movers while gripping components among a plurality of movers.
In the work transport apparatus disclosed in Japanese Patent Application Laid-Open No. 2001-179568, however, there is a problem that attitude change mechanisms need to be installed adjacent to the work transport apparatuses for respective processes and therefore a large installation space needs to be secured. Further, when a processing position of a processing face in each process is changed, it is necessary to again adjust the installed attitude change mechanism every time, and it takes time for such adjustment.
When the position control of movers disclosed in Japanese Patent Publication No. H7-86772 is performed, it is possible to transport a carriage while maintaining a constant distance between two movers. However, position control of a plurality of movers needs to be performed along with a mover of a low moving speed, which results in a limited moving speed of a carriage.
Further, in the transport apparatus disclosed in Japanese Patent Publication No. H7-86772, it is necessary to detect the positions in real time in synchronization with a control cycle and control the drive timings for a plurality of movers. Therefore, in a transport apparatus using a movable magnet-type linear motor, a system needs to be configured to manage and control position information of all the carriages on the transport path at a significantly short cycle. Thus, there is a problem of increased complexity and size of a system.